The present invention relates in general to self-moving metal cutting equipment, and in particular to a new and useful robot structure which carries one or more cutting heads for cutting the fins from a tube and which is moveable along the tube.
Various metal cutting devices are known which have some sort of cutting head such as a torch or mechanical cutter, which is mounted on a carriage and which is moveable for cutting along a workpiece.
According to the present invention, a wheeled carriage carries a pair of arcuate drive rollers that ride against a tube which carries fins to be cut. The carriage also carries one or more cutting heads which may be in the form of torches or mechanical cutters, for cutting one or more fins connected to the tube. Spring loaded wheels riding against the fins of adjacent tubes press the carriage toward the tube having the fins to be cut for guiding the carriage as it is driven along the tube by the drive rollers.
Various devices are known which include cutting torches which are mounted on carriages that can be moved along a selected path to cut a workpiece.
U.S. Pat. No. 2,617,644 to Helmkamp and U.S. Pat. No. 2,782,024 to Demmer et al, disclose universal gas torch cutting machines. The term "univeral" means that the torch can move throughout a horizontal plane so that a pattern followed by a tracer connected to the torch can be cut into the workpiece. In Helmkamp, the apparatus rests on the workpiece and a motorized tracer, attached to one end of a bar that is slidably mounted through a wheeled carriage, traces a pattern that is then duplicated by the torch attached to the other end of the bar. The wheeled carriage rolls along a tubular monorail which rests on the workpiece. Demmer, et al is merely a modification of Helmkamp, and employs a pair of tubular monorails to support two wheeled carriages while a tracer traces a pattern that will be followed by a plurality of cutting torches.
Neither Helmkanp nor Demmer, et al teach or suggest a wheeled carriage that rides on and is driven by contact of arcuate drive rollers with a workpiece itself. Further, since these references are designed to rest upon the pattern and workpiece, they contain no spring loaded wheels that press against fins of an adjacent tube to keep the wheeled carriage positioned between the workpiece and the adjacent tube.
U.S. Pat. No. 2,737,383 to Baumgartner discloses a three dimensional cutting apparatus comprising a torch mounted on a motorized carriage. The carriage moves horizontally and then vertically along a pair of parallel round bar tracks which are separate from the workpiece and which have a predetermined contour. Upper and lower wheels, having a shape matching the round bar tracks, are used to position and move the motorized carriage. Baumgartner thus provides a track that is separate from the workpiece on which his device travels.
U.S. Pat. No. 3,071,360 to Scarince discloses a self-propelled flat stock cutting machine employing a torch and at least two sets of pressure rollers. Particular reference is made to FIG. 9 of the reference that shows a stationary embodiment. Grooved rollers allow the carriage to roll on the frame of the machine. These rollers do not drdive by contact with the workpiece itself.
U.S. Pat. No. 3,190,628 to Litzka discloses a cutting apparatus for a horizontal I-beam according to a cam pattern that is traced on a revolving drum. While the apparatus rides on the I-beam itself, a separate gear rack and pinion are used to propel the carriage along the beam.
U.S. Pat. No. 4,327,898 to Grant et al discloses a traveling torch that rides along a separate track made of simple angle iron, and laid upon or near the workpiece. Again, there is nothing in Grant et al to teach or support that the geometrical features of the workpiece itself can be used for guiding or driving a motorized torch.
U.S. Pat. No. 4,405,117 to Ohlaug and U.S. Pat. No. 4,469,311 to Laing disclose manual and motorized hand torches with wheeled means for positioning the tip of the torch at a predetermined distance from the workpiece.